In a series of tweets on Friday night, Elon Musk said he plans to launch his red Tesla Roadster to Mars in 2018.

Multiple sources now confirm Musk is serious, even if the tech mogul and billionaire had a good laugh or two at the expense of journalists over the weekend. Based on Musk’s history and the reported capabilities of his new rocket, there’s good reason to believe him.

And in March, Musk said he plans to launch “[s]illiest thing we can imagine” during the first flight of Falcon Heavy. The rocket is SpaceX’s biggest and newest launcher, and one that’s capable of sending a payload of 37,000 pounds (or nearly 14 Tesla Roadsters’ worth of mass) to Mars.

The inaugural Falcon Heavy launch will occur in January 2018, Musk confirmed this week.

“Payload will be my midnight cherry Tesla Roadster playing Space Oddity. Destination is Mars orbit,” Musk tweeted on Friday, referencing the song by David Bowie. “Will be in deep space for a billion years or so if it doesn’t blow up on ascent.”

Musk seemed to further confirm his plans in an impromptu question-and-answer session that evening.

“Just to reiterate, the payload for the first Falcon Heavy rocket will be a Tesla electric car, playing Space Oddity, heading for Mars,” wrote a user named J.C.

SpaceX employees also appeared to confirm the claim. Joy Dunn, an engineer at the company, tweeted on Friday that the first Falcon Heavy payload had been announced.

She said “this is going to be so awesome” and later added, “oh this is legit and of course there will be cameras!”

Musk also initially confirmed his plans to The Verge on Friday, writing “it’s so real” in email to the outlet. However, The Verge updated its story on Saturday, writing that, in a follow-up email, “Musk told us he ‘totally made it up.'”

Business Insider reached SpaceX, though the company declined to comment on the record.

We also contacted Musk directly, but he did not immediately reply. NASA also did not immediately answer our questions about Musk’s stated plan to launch a car to Mars orbit.

Despite the back-and-forth, the claim appears to be legitimate. Musk reportedly told Eric Berger, Ars Technica’s senior space editor, that the mission was “100 percent real” after The Verge’s story was updated, and Berger later tweeted that two SpaceX officials had also confirmed his claim.

“The Roadster to Mars payload is real,” the second SpaceX official reportedly told Berger.